Manufacture of fibers, particularly glass fibers



Oct. 13,- 1964 M. LEVECQUE ETAL 3,152,878 MANUFACTURE OF FIBERS, PARTICULARLY GLASS FIBERS Filed 'July 20, 1960 5 l\ VIII], 7 VIII], 7 a 97 a 9 4 A r 4 4 7 9 4 9 a 4' I i a, ,2

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INVENTOR6 Mazes; qua-cam! M42054 Mqweu ATTORNEY "MANUFACTURE United States Patent 3,l2,$78 0F FIBERS, PARTICULARLY GLASS FIBERS Marcel Levesque, Saint-Gratien, and Marcel Mahru, Paris, France, assignors to Compagnie de Saint-Gohain,

Neuilly-sur-Seine, France, a corporation of France Filed July 20, 1%0, Ser. No. 44,204 Claims priority, application France Aug. 7, 1959 v 4 Claims. (6i. 65-14) The present invention relates to the manufacture of fibers of thermoplastic materials, particularly glass fibers,

. in which the material in' the molten state contained in a proved mechanisms and devices for the efficient production of these fibers. These improvements serve to'impart better mechanical properties to the fibers which are produced and/or appreciable increase in the production of the fibers.

According to a first feature of the invention, the gaseous "current is passed into an annular passage surrounding the rotating body, this passage'being defined by the peripheral wall of said body and by an exterior wall; the

relative positions of these walls being such that the space between therndecreases progressively from the entrance end of the gaseous current toits outlet end.

It has beenestablished that the converging shape given this annular passage results in a better quality of the fibers which are produced, particularly'from the mechanical point of view, and especially because of their resistance to traction orpulling. In fact, the shape of the annular channel serves to increase the speed of the gaseous current during its passage in contact with the periphery of the rotating body, thereby regulating its temperature while travelling along the height of the peripheral band or wall of this body, this temperature otherwise tending to decrease toward the bottom of the band. .IIl'fiddltlOl], a better drawing-out action is obtained on the filaments discharged from the lower rows of holes of the peripheral band.

According to another feature of the invention, the, (gaseous current acting on the threads leaving the orifices of the centrifuge body is channeled only over the upper part of the peripheral band. The exterior wall acting to 'production of the apparatus, while obtaining uniform fibers of excellent mechanical quality. Otherwise, that is, if the annular passage extended over the entire height of the peripheral band, only a very small dimension could be given to this height, for the fibers whose numbers increase constantly from top to bottom, would collect in a space too small for their volume and would tend to stick to one another.

This disposition of the exterior wall adjacent to only the upper part of the peripheral band of the centrifuge, allows utilization of induction heating of the lower part of the band to regulate its temperature, when use is made of a metallic wall.

The invention also contemplates the utilization of a blower ring concentric with the rotating body, and placed outside the wall defining the annular drawing-out gas passage, the gases leaving this ring having the effect of facilitating the evacuation of the fibers and of assuring a complete attenuation thereof.

The invention makes possible the obtention of layers or cushions composed of fine, long fibers, characterized by a high degree of elasticity.

Hereinafter are described by way of non-limiting example, several embodiments of the improvements according to the invention.

In-this description reference is made to the attached drawings wherein:

FIG. 1 is a vertical cross-section of one embodiment of the invention featuring a converging annular passage for the attenuating gases;

FIG. 2 is a vertical cross-section of a second embodiment of the invention featuring an exterior wall cooperating with only the. upper part of the peripheral wall of the centrifuge;

FIG. 3 is a vertical cross-section of a modified embodiment of that shown in FIG. 2, including a blower ring and induction heating for the lower portion of the peripheral wall;

FIG. 4 is a vertical cross-sectional view of a modified embodiment of that shown in FIG. 1, including a blower ring; and p 7 FIG. 5 is a vertical cross-sectional view of still another modified embodiment of that shown in FIG. 1, wherein the exterior wall is of limited depth and cooperates with only the upper part of the peripheral wall of the centrifuge. t

In the embodiments of the invention shown in FIGS. 1, 4 and 5, the hollow rotating centrifuge body 1 is provided with a cylindrical peripheral wall 2 having a plurality of rows of orifices 3 therein through which'the molten material which is fed to the interior of the body is projected in the form of threads.

The gaseous current at high temperature and velocity issues from combustion chamber 4, which is ring-shaped and is disposed above and surrounds the centrifuge. The chamber may be. provided with a continuous annular slot 5, concentric with the rotating body, through which the gaseous fluid escapes.

In the embodiment shown in FIG. 1, the gaseous current is channeled, from slot 5 to the last row of projection orifices 3, by an exteriorwall, which is placed in the prolongation of the outer lip of slot 5 and which is inclined with respect to the. peripheral band 2 so as to form a converging annular channel for the hot gaseous blast. This position of the wallhas the effect of progressively increasing the speed of the gaseous current from the upper part of the peripheral band to the lower part. This improves the attenuating action on the fibers issuing from the lower rows of orifices which generally are affected by the lowering in temperature of the gaseous blast adjacent thereto.

In the embodiment shown in FIG. 2, the centrifuge body 1' is provided with a frusto-conical wall 2 having a large number of superposed rows of orifices therein. The annular combustion chamber 4 with the slot 5 therein, is disposed to sweep the hot blast issuing from An outer wall 7, l

The gaseous blast, on leaving the zone where the wall is placed, presents characteristics of speed and temperatures practically identical with those of the current at the level of outlet lips of annular slot 5. Thus, it is seen that the total heigh of the band may be increased by a value equal to that of the wall 7, without altering the quality of the fibers, hence making possible an increase in the number of rows of orifices and consequently in the output of the apparatus.

In both of the arrangements shown in FIGS. 1 and 2, it is advantageous to cool the outer walls 6 and 7, respectively.

FIG. 3 illustrates an arrangement analogous to that of FIG. 2, but which comprises, in addition, a blower ring 8 Whose orifice 9 may be continuous and concentric with the rotating body 1". It is desirable to place this hing in such a way that the blower orifices are practically at the level of the lower part of wall 7. The gas jet leav- 'ing orifice 9 causes the induction of outer air and acts on the fibers below the rotating body to facilitate their evacuation.

Also, a winding 10 may be provided which is traversed by a high frequency current for the induction heating of the lower part of the peripheral band, in order to maintain this band at a suitable temperature.

FIG. 4 shows an arrangement analogous to that shown in FIG. 1, but which comprises, besides, a blower ring 8' whose orifice 9' may be continuous and concentric with the rotating body. It is desirable to place this ring in such a way that the blower orifice is at about the level of the lower part of wall 6. The gas jet leaving orifice 8 causes the induction of outer air and acts on the fibers under the rotating body to facilitate their evacuation.

In the embodiment shown in FIG. 5, the hollow rotating body 1 resembles that shown in FIGS. 1 and 4, having a cylindrical peripheral band 2 provided with a large number ofrows of orifices 3, through which the melted material is projected in the form of threads. The gaseous current at high temperature and velocity is produced in combustion chamber 4. This chamber is inthe shape of a ring and may be provided with avcontinuous slot 5, concentric with the rotating body, through which the fluid gas escapes.

An outer wall 6', placed in the prolongation of the cut er lip of slot 5, channels the gaseous current. The height of this outer wall 6' is less than that of the peripheral band, and is in general between one-third and one-half of the height of band 2;

In the embodiment shown in FIG. 5, the outer wall 6 is inclined with respect to peripheral band 2, so as to form a converging channel.

As explained; in conjunction with FIG. 2, the gaseous blast, upon leaving the zone where the wall is placed, presents characteristicsfof speed and temperature practically identical. to those of the current at the level of the oulet lips of slot 5, except for the vaniation' in speed occasioned by the narrowing of the annular channel at the outlet end. It is therefore seen that the total height of the band 2 may be increased by a value equal to that of the wall, without altering the quality of the fibers, and hence an increase in number of rows of orifices, and therefore increased production of the apparatus.

As is the case with the arrangements shown in FIGS. 1 and 2, and the walls 6 and 7 disclosed therein, as well as those corresponding walls illustrated in the other figures, it is desirable to cool the outer wall 6' in the arrangement shown in FIG. 5.

We claim:

1. An apparatus for manufacturing fibers of thermoplastic material comprising a hollow centrifuge rotatable about a vertical axis and receiving the heated thermoplastic material in the interior thereof, said centrifuge having a peripheral wall of substantial height provided with a plurality of superposed rows of orifices therein for projecting the fibers therethrough by centrifugal force, a combustion chamber surrounding said centrifuge and provided with an annularly-shaped slot for directing an annular hot gaseous blast onto the fibers issuing therefrom in a direction transverse to the planes of emission thereof, an annular channel for said gaseous blast defined on its inner boundary by said peripheral wall and on its outer boundary by an exterior wall having its upper end substantially coinciding with the outer edge of said slot and its lower end convering towards said peripheral wall to reduce the crosssection of said annular channel towards its outer end, thereby to progressively increase the velocity of the gaseous blast in the course .of its traverse across the rows of orifices from the upper end of the wall, and consequently to attenuate the fibers issuing from all the rows of orifices substantially uniformly.

2. An apparatus as set forth in claim 1 wherein said exterior wall is of substantially the same height as said peripheral wall. t

3. An apparatus as set forth in claim 2, including an annular blowing chamber surrounding said exterior wall and provided with an annularly-shaped blower slot.

4. An apparatus as set forth in claim 3 wherein said blower slot is disposed at substantially the same level as the lower end of said exterior wall, to effect the induction of outer air at the outlet of said channel and thereby to facilitate the evacuation of. the fibers thereat.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Apr. 30, 1958 

1. AN APPARATUS FOR MANUFACTURING FIBERS OF THERMOPLASTIC MATERIAL COMPRISING A HOLLOW CENTIFUGE ROTATABLE ABOUT A VERTICAL AXIS AND RECEIVING THE HEATED THERMOPLASTIC MATERIAL IN THE INTERIOR THEROF, SAID CENTRIFUGE HAVING A PERIPHERAL WALL OF SUBSTANTIAL HEIGHT PROVIDED WITH A PLURALITY OF SUPERPOSED ROWS OF ORIFICES THEREIN FOR PROJECTING THE FIBERS THERETHJROUGH BY CENTRIFUGAL FORCE, A COMBUSTION CHAMBER SURROUNDING SAID CENTRIFUGE AND PROVIDED WITH AN ANNULARLY-SHAPED SLOT FOR DIRECTING AN ANNULAR HOT GASEOUS BLAST ONTO THE FIBERS ISSUING THEREFROM IN A DIRECTION TRANSVERSE TO THE PLANES OF EMISSION THEREOF, AN ANNULAR CHANEL FOR SAID GASEOUS BLAST DEFINED ON ITS INNER BOUNDARY BY SAID PERIPHERAL WALL AND ON ITS OUTER BOUNDARY BY AN EXTERIOR WALL HAVING IT UPPER END SUBSTANTIALLY COINCIDING WIHT THE OUTER EDGE OF SAID SLOT AND IT LOWER END CONVERING TOWARDS SAID PERIPHERAL WALL TO REDUCE THE CROSS-SECTION OF SAID ANNULAR CHANNEL TOWARDS ITS OUTER END, THEREBY TO PROGRESSIVELY INCREASE THE VELOCITY OF THE GASEOUS BLAST IN THE CORSE OF ITS TRAVERSE ACROSS THE ROWS OF ORIFICES FROM THE UPPER END OF THE WALL, AND CONSEQUENTLY TO ATTENUATE THE FIBERS ISSUING FROM ALL THE ROWS OF ORIFICES SUBSTANTIALLY UNIFORMLY. 